The disclosure is based on a brake application system for vehicles, particularly for rail vehicles, containing a wear adjuster as part of a brake actuator having a helical gear which is provided with a threaded spindle and a nut to be screwed to the threaded spindle, as the screw connection parts.
A brake application system of this type is known from European Patent Document EP 0 699 846 A2. The wear adjuster for rail vehicle brakes in the form of tie rod and plunger rod adjusters which, in the case of a brake pad and brake disc wear, keep the brake pad play constant. This takes place by a change of length of the helical gear, in the case of plunger rod adjusters, an increasing adjuster length causing a reduction of the brake pad play. The drive of the known helical gear operates mechanically by a brake linkage with a plunger rod which, in the event of an excess stroke of a brake actuator constructed as a pneumatic cylinder—piston driving gear, is operated by a rocket lever. An emergency release of the brake acted upon by braking power takes place by the pneumatic brake actuator. For the auxiliary release in the case of a brake pad exchange, the threaded spindle is rotated manually.
The present brake application system includes one screw connection part of the helical gear being electrically driven for the wear adjustment and the other screw connection part of the helical screw being electrically driven for the emergency and/or auxiliary release of the brake.
As a result of the electric drive of the one screw connection part of the helical gear for the wear adjustment, the known brake linkage can be eliminated. Since the electric drive unit has a smaller size than the brake linkage, space and weight are saved. The electric control lines can be integrated in a simple manner in different vehicle models and can be laid in a space-saving manner. Furthermore, as a result of the electric operation in comparison to a mechanical operation, a more precise adjusting of the brake pad play can be achieved.
In addition, both functions—the wear adjusting, on the one hand, and the emergency and/or auxiliary release, on the other hand—are implemented by one and the same helical gear. Thus, by a combination of functions in one assembly, additional space and weight can be saved. The auxiliary release, which so far had to be carried out separately in a manual manner for each and on each brake application system, is replaced by an electrically remotely operated auxiliary release, for example, from an engineer's cab of the rail vehicle. In particular, all brake application systems of the rail vehicle can be released by a common and one-time control, whereby the maintenance time is reduced.
For the electric actuating of the one screw connection part, an electric drive unit is provided which consists of an electric motor with a gearing arranged on the output side. The gearing output is rotationally coupled with an electrically actuated screw connection part. The electric motor may be a d.c. motor. The gearing contains a planetary gear axially adjoining the electric motor as well as one or more gearwheel stages arranged behind this planetary gearing.
A clutch by which the one screw connection part, in the event of the presence of an axial force originating from a braking, can be non-rotatably coupled with a non-rotatable part, for example, a housing and otherwise can be uncoupled therefrom. As a result, the screw connection part loaded by way of the caliper levers of the brake application system by the braking power is supported on the housing and not on the electric drive unit. Thus, the electric drive unit can be dimensioned to be smaller, which also contributes to a reduction of the size.
A slip clutch is arranged between the electric drive unit and the one screw connection part. The slip clutch is constructed to slip when stop positions are reached and is otherwise coupling. One stop position is formed, for example, by the application of the brake pads on the brake disc. Another stop position is formed by a screw connection end position in which the one screw connection part is screwed to the stop into the other screw connection part or vice-versa. In the latter case, the one screw connection part would be rotated along with the other screw connection part, and the rotating movement would be undesirably transmitted to the electric drive unit. The slip clutch therefore protects the electric drive unit from impacts when the stop positions are reached in that it slides through in order to permit the motor to softly and gradually conclude its rotating movement and uncouples it from torques introduced by way of other components. The slip clutch is preferably connected between the coupling and the electric drive unit.
The electric drive unit of the one screw connection part can be actuated independently of an electric drive unit of the other screw connection part. As a result, the functions combined in one assembly—the wear adjustment, on the one hand, and the emergency and/or auxiliary release, on the other hand—can be carried out individually and independently of one another.
These and other aspects of the present disclosure will become apparent from the following detailed description of the disclosure, when considered in conjunction with accompanying drawings.